Former oil tycoon Mikhail Khodorkovsky's business partner Platon Lebedev has walked free from prison after Russia's Supreme Court ordered his early release.

"Platon Lebedev left the prison colony... in the Arkhangelsk region around 10:00pm Moscow time (18:00 GMT)," a spokesman for the prison service in the northern region of Russia told the RIA Novosti news agency on Friday.

The Supreme Court on Thursday had ordered 57-year-old Lebedev's immediate release, cutting short his sentence which was due to end in May. He had served a decade behind bars.

Khodorkovsky was released last month after receiving a pardon from President Vladimir Putin on humanitarian grounds and left Russia immediately afterwards.

He is currently in Switzerland with his family.

The high court did not give an official reason for cutting short Lebedev's prison term, but the ruling came as the Kremlin tries to clean up its human-rights image ahead of next month's Winter Olympics in the Black Sea resort of Sochi.

Lebedev was arrested in July 2003. He was Khodorkovsky's co-defendant in two highly controversial trials, which saw both convicted on charges of fraud, tax evasion and money laundering.